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Actuators
Volume 12
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Actuators, Volume 12, Issue 6 (June 2023) – 42 articles

Cover Story (view full-size image): The Hybrid Wing Body (HWB) aircraft has been attracting increasing attention in recent years due to its superior high-speed cruise performance. However, conventional lift devices such as leading-edge slats and Fuller flaps face challenges when applied to this new layout aircraft. Based on existing research on blowing flow control, our study uses a half-mode model of an HWB layout with blowing slots on the leading and trailing edges of the main wing. We investigate the combined blowing lift enhancement scheme for the HWB via Computational Fluid Dynamics (CFD) methods and wind tunnel tests. This research explores the flow characteristics and mechanism of action under blowing control, providing new insights and methods to improve the overall performance of the HWB layout. View this paper
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21 pages, 5713 KiB  
Article
Development of an Adaptive Fuzzy Sliding Mode Controller of an Electrohydraulic Actuator Based on a Virtual Prototyping
by Nguyen Huu Tho, Vo Ngoc Yen Phuong and Le Thanh Danh
Actuators 2023, 12(6), 258; https://doi.org/10.3390/act12060258 - 20 Jun 2023
Cited by 3 | Viewed by 1280
Abstract
The EHA (electro hydraulic actuator) has a notable advantage over conventional hydraulic actuators as it uses a closed-loop circuit, reducing the size and volume of oil, and eliminates pressure losses caused by valve orifices. However, accurate control performance of EHA is difficult to [...] Read more.
The EHA (electro hydraulic actuator) has a notable advantage over conventional hydraulic actuators as it uses a closed-loop circuit, reducing the size and volume of oil, and eliminates pressure losses caused by valve orifices. However, accurate control performance of EHA is difficult to achieve using a traditional PID (proportional integral derivative) controller due to the strongly nonlinear, time-varying, and unknown dynamics of the system. Hence this paper seeks to address this problem by proposing a design of an intelligent controller for the EHA. The proposed adaptive fuzzy sliding mode controller (AFSMC) is developed as a hybrid of the adaptive, fuzzy logic, and sliding mode algorithms. To reduce costs and time, a virtual prototype approach is also proposed instead of experimentations to evaluate the performance of the proposed controller. The virtual model of the EHA is built in Amesime software, and then embedded into Matlab/Simulink where the AFSMC is developed and tested to obtain the position responses of the EHA. The results show that the AFSMC is highly successful and more efficient than the traditional PID at controlling the position of the piston accurately. Full article
(This article belongs to the Special Issue Intelligent and Precision Control for Mechatronic/Electro-Hydraulic Systems)
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18 pages, 4425 KiB  
Article
Measuring the Precision of the Oculus Quest 2’s Handheld Controllers
by Diogo Pereira, Vitor Oliveira, João L. Vilaça, Vítor Carvalho and Duarte Duque
Actuators 2023, 12(6), 257; https://doi.org/10.3390/act12060257 - 20 Jun 2023
Cited by 1 | Viewed by 3697
Abstract
Consumer-grade virtual reality systems have become increasingly accessible over the last years, making these great options for psychological and physiological medical use. This paper studies the precision of one available system, the Oculus Quest 2. We investigated studies that approached testing of these [...] Read more.
Consumer-grade virtual reality systems have become increasingly accessible over the last years, making these great options for psychological and physiological medical use. This paper studies the precision of one available system, the Oculus Quest 2. We investigated studies that approached testing of these types of systems using manual systems and automated systems using robot arms and decided to use the latter method for our evaluation. A setup was created where the robotic arm would perform diverse exercises, with the Quest controller attached to it while the headset was either stationary or being worn by a participant. The results show that these systems are precise enough to measure movements that would not be noticed by therapists during traditional rehabilitation and are therefore adequate for medical use. Full article
(This article belongs to the Special Issue Advanced Technologies and Applications in Robotics)
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22 pages, 5074 KiB  
Article
Computational Control Strategy for Reducing Medial Compartment Load in Knee Bracing with Embedded Actuator
by Mahdi Bamdad and Amirhosein Javanfar
Actuators 2023, 12(6), 256; https://doi.org/10.3390/act12060256 - 19 Jun 2023
Viewed by 1399
Abstract
Medial unloader braces represent a primary noninvasive approach for alleviating knee pain. However, conventional valgus unloader braces, while reducing load on the medial compartment, inadvertently increase load on the lateral compartment through rotation from adduction to abduction. This phenomenon significantly elevates the risk [...] Read more.
Medial unloader braces represent a primary noninvasive approach for alleviating knee pain. However, conventional valgus unloader braces, while reducing load on the medial compartment, inadvertently increase load on the lateral compartment through rotation from adduction to abduction. This phenomenon significantly elevates the risk of damage to the lateral compartment. To address this issue, we introduce a novel embedded actuation mechanism that unloads the knee using a pioneering computational procedure. By considering the knee osteoarthritis condition, we propose the calculation of the adduction knee angle and cartilage penetration depth as surrogate parameters for assessing knee pain. Accordingly, the newly developed unloader brace redistributes the load by precisely correcting the abduction angle. Additionally, we determine the maximum required torque for effectively tracking the desired abduction angle. Then, the saturated torque through the robust control method is applied in the presence of interaction force uncertainty between the orthosis and the user. A very small femur rotation change (1.7°) from adduction to abduction in the frontal plane is adequate to significantly reduce the medial contact force (around 886 N). The required robust external abduction torque is determined to be 27.6 Nm. The result shows that the novel procedure and brace prevent excessive overloading of the lateral compartment while it unloads the medial compartment sufficiently. This innovative approach offers significant potential for optimizing unloader brace design and enhancing the management of knee osteoarthritis. Full article
(This article belongs to the Special Issue Actuators in Assistive and Rehabilitation Robotics)
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19 pages, 433 KiB  
Article
Fault Detection and Reliable Controller Design for Fractional-Order Systems Based on Dynamic Observer
by He Li, Jie Li, Chao Deng and Yuanxin Li
Actuators 2023, 12(6), 255; https://doi.org/10.3390/act12060255 - 19 Jun 2023
Cited by 1 | Viewed by 858
Abstract
In this paper, the problem of the fractional-order linear systems’ simultaneous fault detection and reliable control (SFDC) in the finite frequency domain is investigated. A dynamic observer aimed at detecting faults is designed, which also generates state estimation signals. In particular, it is [...] Read more.
In this paper, the problem of the fractional-order linear systems’ simultaneous fault detection and reliable control (SFDC) in the finite frequency domain is investigated. A dynamic observer aimed at detecting faults is designed, which also generates state estimation signals. In particular, it is found that the proposed dynamic-observer-based controller can achieve a better H∞ performance. We derived the detector and controller’s design conditions to achieve H− fault sensitivity performance and H∞ interference attenuation performance in the limited frequency domain based on the generalized KYP lemma, which can achieve a better disturbance attenuation performance and fault sensitivity performance. Finally, the simulation results show the designed method’s effectiveness. Full article
(This article belongs to the Special Issue Sensor and Actuator Attacks of Cyber-Physical Systems)
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22 pages, 7527 KiB  
Article
Evolutionary Computation-Based Active Mass Damper Implementation for Vibration Mitigation in Slender Structures Using a Low-Cost Processor
by César Peláez-Rodríguez, Alvaro Magdaleno, Álvaro Iglesias-Pordomingo and Jorge Pérez-Aracil
Actuators 2023, 12(6), 254; https://doi.org/10.3390/act12060254 - 18 Jun 2023
Cited by 2 | Viewed by 1135
Abstract
This work is devoted to design, implement and validate an active mass damper (AMD) for vibration mitigation in slender structures. The control law, defined by means of genetic algorithm optimization, is deployed on a low-cost processor (NI myRIO-1900), and experimentally validated on a [...] Read more.
This work is devoted to design, implement and validate an active mass damper (AMD) for vibration mitigation in slender structures. The control law, defined by means of genetic algorithm optimization, is deployed on a low-cost processor (NI myRIO-1900), and experimentally validated on a 13.5-m lively timber footbridge. As is known, problems arising from human-induced vibrations in slender, lightweight and low-damped structures usually require the installation of mechanical devices, such as an AMD, in order to be mitigated. This kind of device tends to reduce the movement of the structure, which can be potentially large when it is subjected to dynamic loads whose main components match its natural frequencies. In those conditions, the AMD is sought to improve the comfort and fulfil the serviceability conditions for the pedestrian use according to some design guides. After the dynamic identification of the actuator, the procedure consisted of the experimental characterization and identification of the modal properties of the structure (natural frequencies and damping ratios). Once the equivalent state space system of the structure is obtained, the design of the control law is developed, based on state feedback, which was deployed in the low-cost controller. Finally, experimental adjustments (filters, gains, etc.) were implemented and the validation test was carried out. The system performance has been evaluated using different metrics, both in the frequency and time domain, and under different loads scenarios, including pedestrian transits to demonstrate the feasibility, robustness and good performance of the proposed system. The strengths of the presented work reside in: (1) the use of genetic evolutionary algorithms to optimize both the state estimator gain and the feedback gain that commands the actuator, whose performance is further tested and analyzed using different fitness functions related to both time and frequency domains and (2) the implementation of the active control system in a low-cost processor, which represents a significant advantage when it comes to implement this system in a real structure. Full article
(This article belongs to the Special Issue Actuators and Dampers for Vibration Control: Damping and Isolation Applications - Volume II)
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17 pages, 7811 KiB  
Article
Hybrid Visual Servo Control of a Robotic Manipulator for Cherry Tomato Harvesting
by Yi-Rong Li, Wei-Yuan Lien, Zhi-Hong Huang and Chun-Ta Chen
Actuators 2023, 12(6), 253; https://doi.org/10.3390/act12060253 - 16 Jun 2023
Cited by 3 | Viewed by 1624
Abstract
This paper aims to develop a visual servo control of a robotic manipulator for cherry tomato harvesting. In the robotic manipulator, an RGB-depth camera was mounted to the end effector to acquire the poses of the target cherry tomatoes in space. The eye-in-hand-based [...] Read more.
This paper aims to develop a visual servo control of a robotic manipulator for cherry tomato harvesting. In the robotic manipulator, an RGB-depth camera was mounted to the end effector to acquire the poses of the target cherry tomatoes in space. The eye-in-hand-based visual servo controller guides the end effector to implement eye–hand coordination to harvest the target cherry tomatoes, in which a hybrid visual servo control method (HVSC) with the fuzzy dynamic control parameters was proposed by combining position-based visual servo (PBVS) control and image-based visual servo (IBVS) control for the tradeoff of both performances. In addition, a novel cutting and clipping integrated mechanism was designed to pick the target cherry tomatoes. The proposed tomato-harvesting robotic manipulator with HVSC was validated and evaluated in a laboratory testbed based on harvesting implementation. The results show that the developed robotic manipulator using HVSC has an average harvesting time of 9.40 s/per and an average harvesting success rate of 96.25% in picking cherry tomatoes. Full article
(This article belongs to the Special Issue Actuators in Robotic Control: Volume II)
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17 pages, 10239 KiB  
Article
Influence of Nonlinear Characteristics of Planetary Flywheel Inerter Actuator on Vehicle Active Suspension Performance
by Zheng Ge, Guangping Li, Shixiang Chen and Weirui Wang
Actuators 2023, 12(6), 252; https://doi.org/10.3390/act12060252 - 16 Jun 2023
Cited by 1 | Viewed by 951
Abstract
The planetary flywheel can significantly reduce the weight of the flywheel, allowing the inerter to be lightweight. When a planetary flywheel ball screw inerter-based active actuator is used in a vehicle suspension system, the nonlinear features of the actuator affect vehicle performance. The [...] Read more.
The planetary flywheel can significantly reduce the weight of the flywheel, allowing the inerter to be lightweight. When a planetary flywheel ball screw inerter-based active actuator is used in a vehicle suspension system, the nonlinear features of the actuator affect vehicle performance. The planetary flywheel inerter actuator’s nonlinear dynamic model is constructed in this study based on the dynamic features of the planetary flywheel ball screw inerter and the electromagnetic torque generating mechanism of the permanent magnet synchronous motor. The impact of ball screw–nut friction, transmission clearance, planetary gear friction, and gear backlash on the performance of an active tuned inerter damper suspension is then investigated. As a result, the impact and sensitivity of numerous nonlinear parameters on suspension performance are shown, providing a theoretical foundation for the design of planetary flywheel inerter actuator and active inerter suspension. Full article
(This article belongs to the Section Actuators for Land Transport)
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19 pages, 5110 KiB  
Article
Multi-Physics Simulation and Experimental Verification of Magnetorheological Damper with Additional Stiffness
by Huijun Liang, Jie Li, Yongsheng Wang, Mingkun Liu, Jie Fu, Lei Luo and Miao Yu
Actuators 2023, 12(6), 251; https://doi.org/10.3390/act12060251 - 16 Jun 2023
Cited by 3 | Viewed by 1335
Abstract
Single-rod magneto-rheological dampers (MRD) have the advantages of a simple mechanism, high reliability, and broad application range. They are widely used in various semi-active vibration control fields. However, their working mode requires a compensating mechanism to perform volume compensation on the rod, leading [...] Read more.
Single-rod magneto-rheological dampers (MRD) have the advantages of a simple mechanism, high reliability, and broad application range. They are widely used in various semi-active vibration control fields. However, their working mode requires a compensating mechanism to perform volume compensation on the rod, leading to additional stiffness for the system. Ignoring this point makes it tough to establish an accurate mechanical model to describe its performance in the design stage, affecting its application. To address this issue, this study proposes a multi-physics simulation model based on gas compensation for single-rod MRD to characterize their mechanical performance accurately. Firstly, the mechanism and mechanical model of the single-rod gas compensation MRD are introduced. Secondly, considering that its performance is affected by the coupling effect of multiple physical fields, including magnetic, flow, and solid mechanics fields, the control equations and boundary conditions of each field are analyzed separately, and a multi-physics coupling simulation model is established by COMSOL. In particular, the gas compensation unit is considered in the multi-physics simulation model. The effect of the compensating mechanism on the mechanical performance of the damper under different excitation speeds, currents, and initial pressures is analyzed. Finally, the accuracy of the proposed method is verified through the demonstration power test. The results show that the simulation can describe the additional stiffness in the damper. The average error between experimental value and simulation value is 7%. This demonstrates the degree of agreement between the experiment and simulation. Full article
(This article belongs to the Special Issue Active, Semi-active and Passive Vibration Control)
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15 pages, 6771 KiB  
Communication
Numerical Investigation of Effect of Structural Parameters on the Performance of a Combustion-Driven Sparkjet Actuator
by Hai Chen, Yan Zhou, Zhenbing Luo and Pan Cheng
Actuators 2023, 12(6), 250; https://doi.org/10.3390/act12060250 - 15 Jun 2023
Viewed by 735
Abstract
With the aim of increasing the momentum jet and obtaining better environmental adaptability, this study designs a new type of actuator combining a sparkjet actuator and a combustion-driven actuator. Numerical simulation shows that the combustion-driven sparkjet actuator has a higher velocity and mass [...] Read more.
With the aim of increasing the momentum jet and obtaining better environmental adaptability, this study designs a new type of actuator combining a sparkjet actuator and a combustion-driven actuator. Numerical simulation shows that the combustion-driven sparkjet actuator has a higher velocity and mass rate compared to the sparkjet actuator when the length and orifice diameter are 6.5 mm and 1.3 mm, respectively, while the saturation work frequency is almost the same. A parameter study shows that as the volume increases, the pressure, orifice velocity, and mass rate of the combustion-driven sparkjet actuator increase. By contrast, the saturation work frequency decreases. Moreover, as the orifice diameter decreases, the orifice peak velocity, temperature, and pressure increase, whereas the mass flow rate and saturation work frequency decrease. Full article
(This article belongs to the Section Miniaturized and Micro Actuators)
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18 pages, 6822 KiB  
Article
A Hierarchical Control Scheme for Adaptive Cruise Control System Based on Model Predictive Control
by Hongyuan Mu, Liang Li, Mingming Mei and Yongtao Zhao
Actuators 2023, 12(6), 249; https://doi.org/10.3390/act12060249 - 14 Jun 2023
Cited by 1 | Viewed by 1158
Abstract
An adaptive cruise control (ACC) system can improve safety and comfort during driving by taking over longitudinal control of the vehicle. It requires the coordination between the upper-layer controller and the lower-layer actuators. In this paper, a hierarchical anti-disturbance cruise control architecture based [...] Read more.
An adaptive cruise control (ACC) system can improve safety and comfort during driving by taking over longitudinal control of the vehicle. It requires the coordination between the upper-layer controller and the lower-layer actuators. In this paper, a hierarchical anti-disturbance cruise control architecture based on electronic stability control (ESC) system is proposed. The upper-layer controller outputs the desired longitudinal acceleration or deceleration to the lower-layer actuators. In order to improve the accuracy of model prediction and achieve the coordinated control of multiple objectives, an upper-layer model prediction cruise controller is established based on feedback control and disturbance compensation. In addition, based on the hydraulic control unit (HCU) model and the vehicle longitudinal dynamics model, a lower-layer nonlinear model predictive deceleration controller is proposed in order to solve the problems of pressure fluctuations and the low accuracy of small decelerations when ESC is used as the actuator for the ACC system. Finally, the simulation and experimental tests were carried out. The results show that the proposed control architecture can improve the stability and comfort of the cruise control process. Moreover, compared with the traditional PID deceleration controller, it effectively improves the deceleration control accuracy. Full article
(This article belongs to the Section Control Systems)
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14 pages, 6895 KiB  
Article
Characteristic Analysis of a New Structure Eccentric Harmonic Magnetic Gear
by Libing Jing, Youzhong Wang, Dawei Li and Ronghai Qu
Actuators 2023, 12(6), 248; https://doi.org/10.3390/act12060248 - 14 Jun 2023
Viewed by 1013
Abstract
An eccentric harmonic magnetic gear (EHMG) is better suited for situations requiring larger transmission ratios than magnetic-field-modulated magnetic gears. In the meantime, to increase the torque density even further, a new structure for EHMGs is presented in this paper. The stator’s permanent magnets [...] Read more.
An eccentric harmonic magnetic gear (EHMG) is better suited for situations requiring larger transmission ratios than magnetic-field-modulated magnetic gears. In the meantime, to increase the torque density even further, a new structure for EHMGs is presented in this paper. The stator’s permanent magnets (PMs) are irregularly distributed, while the rotor’s PMs are applied to a fan-shaped structure. Moreover, a Halbach array is adopted in both the rotor and the stator. A two-dimensional finite element (FE) model of the proposed EHMG is developed, and the flux density distribution and torque of the EHMG are calculated and verified via FE analysis. When compared to a conventional EHMG, the presented model’s torque increases from 38.04 Nm to 50.41 Nm. In addition, for the sake of avoiding the oscillation and noise caused by resonance, a modal analysis of the proposed model is conducted and the consequences show that it has better antivibration properties. Finally, a prototype is made, a test bench is established, and the correctness and effectiveness of the proposed model are verified. Full article
(This article belongs to the Special Issue Power Electronics and Actuators)
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13 pages, 4426 KiB  
Article
A Magnetic-Controlled Flexible Continuum Robot with Different Deformation Modes for Vascular Interventional Navigation Surgery
by Zili Wang, Ding Weng, Zhaoxin Li, Lei Chen, Yuan Ma and Jiadao Wang
Actuators 2023, 12(6), 247; https://doi.org/10.3390/act12060247 - 14 Jun 2023
Cited by 2 | Viewed by 1812
Abstract
A magnetic-controlled flexible continuum robot (MFCR) is a kind of continuum robot with small-size and flexibility that deforms under controlled magnetic fields, which makes MFCRs easy to fit in special sizes and designs and provides them with the ability to feasibly arrive at [...] Read more.
A magnetic-controlled flexible continuum robot (MFCR) is a kind of continuum robot with small-size and flexibility that deforms under controlled magnetic fields, which makes MFCRs easy to fit in special sizes and designs and provides them with the ability to feasibly arrive at the desired area through certain blood vessel bifurcation. The magnetic drive method is suitable for the miniaturization of soft continuum robots but shows limitations in realizing high flexibility. To achieve miniaturization and high flexibility, in this work, the deformation schemes of a magnetic-controlled flexible continuum robot (MFCR) are proposed, simulated, and experimentally validated. The proposed MFCR includes a soft steering part made of a silicone elastomer with uniformly dispersed NdFeB powder which has a specific magnetization direction. With the actuation of different magnetic fields, the proposed MFCR shows three different deformation modes (C-shape, J-shape, and S-shape) and high flexibility. By using the potential energy model combined with magnetic and elastic potential energy, the quasi-static deformation model of MFCR is built. Through various simulations and experiments, we analyzed and predicted different deformation modes. The results from the experiments demonstrate the accuracy of the deformation model. The results indicate that the MFCR has good control precision and deformation performance with potential applications in robot-assisted minimally invasive surgery. Full article
(This article belongs to the Special Issue Soft Robotics in Biomedical Application)
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23 pages, 9868 KiB  
Article
Research on Fault-Tolerant Control of Distributed-Drive Electric Vehicles Based on Fuzzy Fault Diagnosis
by Shaopeng Zhu, Haojun Li, Guodong Wang, Chenyang Kuang, Huipeng Chen, Jian Gao and Wei Xie
Actuators 2023, 12(6), 246; https://doi.org/10.3390/act12060246 - 13 Jun 2023
Cited by 1 | Viewed by 1120
Abstract
This paper addresses the fault problem in distributed-four-wheel-drive electric vehicle drive systems. First, a fault-factor-based active fault diagnosis strategy is proposed. Second, a fault-tolerant controller is designed to reconstruct motor drive torque based on vehicle stability. This controller ensures that the vehicle maintains [...] Read more.
This paper addresses the fault problem in distributed-four-wheel-drive electric vehicle drive systems. First, a fault-factor-based active fault diagnosis strategy is proposed. Second, a fault-tolerant controller is designed to reconstruct motor drive torque based on vehicle stability. This controller ensures that the vehicle maintains stability by providing fault-free motor output torque based on fault diagnosis results. To validate the effectiveness of the fault diagnosis and fault-tolerant control, SIL simulation is conducted using MATLAB/Simulink and CarSim. A hardware-in-the-loop (HIL) simulation platform with the highest confidence level is established based on NI PXI and CarSim RT. Through the HIL simulation experiments, it is shown that the proposed control strategy can accurately diagnose the operating state of the motor, rebuild the motor torque based on stability, and demonstrate robust stability when the drive system fails. Under various fault conditions, the maximum error in the vehicle lateral angular velocity is less than 0.017 rad/s and the maximum deviation in the lateral direction is less than 0.7 m. These findings substantiate the highly robust stability of the proposed method. Full article
(This article belongs to the Special Issue New Control Schemes for Actuators)
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14 pages, 6727 KiB  
Article
Resonant Self-Actuation Based on Bistable Microswitching
by Joel Joseph, Makoto Ohtsuka, Hiroyuki Miki and Manfred Kohl
Actuators 2023, 12(6), 245; https://doi.org/10.3390/act12060245 - 13 Jun 2023
Viewed by 1303
Abstract
We present the design, simulation, and characterization of a magnetic shape-memory alloy (MSMA) film actuator that transitions from bistable switching to resonant self-actuation when subjected to a stationary heat source. The actuator design comprises two Ni-Mn-Ga films of 10 µm thickness integrated at [...] Read more.
We present the design, simulation, and characterization of a magnetic shape-memory alloy (MSMA) film actuator that transitions from bistable switching to resonant self-actuation when subjected to a stationary heat source. The actuator design comprises two Ni-Mn-Ga films of 10 µm thickness integrated at the front on either side of an elastic cantilever that moves freely between two heatable miniature permanent magnets and, thus, forms a bistable microswitch. Switching between the two states is induced by selectively heating the MSMA films above their Curie temperature Tc. When continuously heating the permanent magnets above Tc, the MSMA film actuator exhibits an oscillatory motion in between the magnets with large oscillation stroke in the frequency range of 50–60 Hz due to resonant self-actuation. A lumped-element model (LEM) is introduced to describe the coupled thermo-magnetic and magneto-mechanical performance of the actuator. We demonstrate that this performance can be used for the thermomagnetic energy generation of low-grade waste heat (T < 150 °C) with a high power output per footprint in the order of 2.3 µW/cm2. Full article
(This article belongs to the Special Issue Cooperative Microactuator Devices and Systems)
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12 pages, 38407 KiB  
Article
Experimental Implementation of a Magnetic Levitation System for Laser-Directed Energy Deposition via Powder Feeding Additive Manufacturing Applications
by Parichit Kumar, Mazyar Ansari, Ehsan Toyserkani and Mir Behrad Khamesee
Actuators 2023, 12(6), 244; https://doi.org/10.3390/act12060244 - 12 Jun 2023
Cited by 2 | Viewed by 1591
Abstract
Magnetic levitation and additive manufacturing (AM) are two fields of significant interest in academic research. The use of non-contact forces for magnetic levitation techniques provides opportunities for adoption within the AM environment. The key goal of this article is to experimentally validate the [...] Read more.
Magnetic levitation and additive manufacturing (AM) are two fields of significant interest in academic research. The use of non-contact forces for magnetic levitation techniques provides opportunities for adoption within the AM environment. The key goal of this article is to experimentally validate the implementation of a magnetic levitation system for Laser-Directed Energy Deposition via Powder Feeding (LDED-PF) Additive Manufacturing applications. Through simulations (conducted in ANSYS Maxwell) and experimental implementation, the levitation system’s stability is tested under a variety of different conditions. The experimental implementation highlights the feasibility of a magnetic levitation system for LDED-PF applications. The levitation system developed is capable of the suspension of non-magnetic materials. The system is also able to maintain stable levitation for extended periods of time. The incorporation of the levitation system into the AM environment may result in an increased maneuverability of non-clamped structures for AM deposition operations. Full article
(This article belongs to the Special Issue Advances in High-Precision Magnetic Levitation Actuators)
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22 pages, 4545 KiB  
Article
Robust Adaptive Composite Learning Integrated Guidance and Control for Skid-to-Turn Interceptors Subjected to Multiple Uncertainties and Constraints
by Yu Bai, Tian Yan, Wenxing Fu, Tong Li and Junhua Huang
Actuators 2023, 12(6), 243; https://doi.org/10.3390/act12060243 - 11 Jun 2023
Cited by 2 | Viewed by 1066
Abstract
This paper investigates a novel robust adaptive dynamic surface control scheme based on the barrier Lyapunov function (BLF), online composite learning, disturbance observer, and improved saturation function. It is mainly designed for a class of skid-to-turn (STT) interceptor integrated guidance and control (IGC) [...] Read more.
This paper investigates a novel robust adaptive dynamic surface control scheme based on the barrier Lyapunov function (BLF), online composite learning, disturbance observer, and improved saturation function. It is mainly designed for a class of skid-to-turn (STT) interceptor integrated guidance and control (IGC) design problems under multi-source uncertainties, state constraints, and input saturation. The serial-parallel estimation model used in this study estimates the system states and provides “critic” information for the neural network and disturbance observer; then, these three are combined to realize online composite learning of the multiple uncertainties of the system and improve the interception accuracy. In addition, the state and input constraints are resolved by adopting the BLF and the improved saturation function, while the design of the auxiliary system ensures stability. Finally, a series of simulation results show that the proposed IGC scheme with a direct-hit intercept strategy achieves a satisfactory effect, demonstrating the validity and robustness of the scheme. Full article
(This article belongs to the Special Issue Dynamics and Control of Aerospace Systems)
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20 pages, 4034 KiB  
Article
Research on Fault Diagnosis of HVAC Systems Based on the ReliefF-RFECV-SVM Combined Model
by Lei Nie, Rouhui Wu, Yizhu Ren and Mengying Tan
Actuators 2023, 12(6), 242; https://doi.org/10.3390/act12060242 - 11 Jun 2023
Cited by 4 | Viewed by 1303
Abstract
A fault diagnosis method of heating, ventilation, and air conditioning (HVAC) systems based on the ReliefF-recursive feature elimination based on cross validation-support vector machine (ReliefF-RFECV-SVM) combined model is proposed to enhance the diagnosis accuracy and efficiency. The method initially uses ReliefF to screen [...] Read more.
A fault diagnosis method of heating, ventilation, and air conditioning (HVAC) systems based on the ReliefF-recursive feature elimination based on cross validation-support vector machine (ReliefF-RFECV-SVM) combined model is proposed to enhance the diagnosis accuracy and efficiency. The method initially uses ReliefF to screen the original features, selecting those that account for 95% of the total weight. The recursive feature elimination based on cross validation (RFECV), based on a random forest classifier, is then applied to select the optimal feature subset according to diagnostic accuracy. Finally, a support vector machine (SVM) model is constructed for fault classification. The method is tested on seven typical faults of the ASHRAE 1043-RP water chiller dataset and three typical faults of an air-cooled self-built air conditioner simulation dataset. The results show that the ReliefF-RFECV-SVM method significantly reduces diagnosis time compared to SVM, shortening it by about 50% based on the ASHRAE 1043-RP dataset, while achieving an overall accuracy of 99.98%. Moreover, the proposed method achieves a comprehensive diagnosis accuracy of 99.97% on the self-built simulation dataset, with diagnosis time the reduced by about 65% compared to single SVM. Full article
(This article belongs to the Section Control Systems)
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19 pages, 15859 KiB  
Article
Development of an Active Physical Interface for Physical Human-Robot Interaction: Investigation of Soft Pneumatic Actuator Straps for Automatic Enclosure System
by Christopher van Vlerken, Felipe Ballen-Moreno, Ellen Roels, Pasquale Ferrentino, Kevin Langlois, Bram Vanderborght and Tom Verstraten
Actuators 2023, 12(6), 241; https://doi.org/10.3390/act12060241 - 09 Jun 2023
Viewed by 1289
Abstract
Wearable robots have become increasingly prevalent in various applications, including rehabilitation, power augmentation, and assistance. However, one of the challenges in designing wearable robots is how to attach them to the human body. The attachment method should be secure, reliable, comfortable, effective, and [...] Read more.
Wearable robots have become increasingly prevalent in various applications, including rehabilitation, power augmentation, and assistance. However, one of the challenges in designing wearable robots is how to attach them to the human body. The attachment method should be secure, reliable, comfortable, effective, and controlled for the user. Moreover, the attachment points should not interfere with the user’s daily activities, and the attachment process should not be time-consuming or complicated. Typical straps nowadays require a time-consuming and cumbersome donning and doffing procedure from therapists for users needing rehabilitation therapy. Therefore, we propose a novel pneumatically actuated soft strap to enclose the limb and automate part of the strapping procedure. This paper proposes a preliminary design utilizing soft bending actuators for attaching physical interfaces to humans, with integrated active elements for facilitating and automating the strapping process. Finite element analysis was conducted to assess pressure requirements, bending curvature, and geometry, with simulation results demonstrating a promising agreement, with a root mean square error (RMSE) of 3.4° in bending angle. In the future, an additional locking mechanism would be required to provide the necessary holding force and fully constrain the limb. Full article
(This article belongs to the Special Issue Actuators in Assistive and Rehabilitation Robotics)
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16 pages, 8365 KiB  
Article
Design and Kinematic Characteristic Analysis of a Spiral Robot for Oil and Gas Pipeline Inspections
by Hongwei Yan, Pengyang Zhao, Canjun Xiao, Dengxiao Zhang, Shaoni Jiao, Haibing Pan and Xi Wu
Actuators 2023, 12(6), 240; https://doi.org/10.3390/act12060240 - 09 Jun 2023
Cited by 3 | Viewed by 1524
Abstract
This study presents a spiral pipeline robot designed for detecting and preventing oil and gas pipeline leakages. A comprehensive analysis of factors such as spiral angle, normal force, pipe material, and operating attitude is conducted based on the robot’s mechanical model in a [...] Read more.
This study presents a spiral pipeline robot designed for detecting and preventing oil and gas pipeline leakages. A comprehensive analysis of factors such as spiral angle, normal force, pipe material, and operating attitude is conducted based on the robot’s mechanical model in a straight pipe. This in-depth investigation determines the optimal spiral angle, normal force, pipeline material, and operating attitude to enhance the robot’s motion stability and traction performance. Using virtual prototype technology, the robot’s traction performance is simulated under various working conditions, normal forces, and attitude angles within the pipeline. An experimental platform is established to verify the impact of deflection angle, normal force, and pipeline material on traction performance. The experimental results and simulation analysis mutually validate each other, providing a reliable reference for robot design and optimization. The spiral pipeline robot and its motion strategy proposed in this study possess both theoretical value and practical application prospects in the field of oil and gas pipeline inspection and maintenance. Full article
(This article belongs to the Special Issue Modeling, Optimization and Control of Robotic Systems)
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14 pages, 5262 KiB  
Article
Evaluation and Simulation Analysis of Mixing Performance for Gas Fuel Direct Injection Engine under Multiple Working Conditions
by Hongchen Wang, Tianbo Wang, Jing Chen, Lanchun Zhang, Yan Zheng, Li Li and Yanyun Sun
Actuators 2023, 12(6), 239; https://doi.org/10.3390/act12060239 - 08 Jun 2023
Viewed by 1073
Abstract
Gas fuel direct injection (DI) technology can improve the control precision of the in-cylinder mixing and combustion process and effectively avoid volumetric efficiency reduction in a compressed natural gas (CNG) engine, which has been a tendency. However, compared with the port fuel injection [...] Read more.
Gas fuel direct injection (DI) technology can improve the control precision of the in-cylinder mixing and combustion process and effectively avoid volumetric efficiency reduction in a compressed natural gas (CNG) engine, which has been a tendency. However, compared with the port fuel injection (PFI) method, the former’s mixing path and duration are shortened greatly, which often leads to poor mixing uniformity. What is worse, the in-cylinder mixing performance would be seriously affected by engine working conditions, such as engine speed and load. Based on this situation, the fluid mechanics software FLUENT is used in this article, and the computational fluid dynamics (CFD) model of the injection and mixing process in a gas-fueled direct injection engine is established. A quantitative evaluation mechanism of the in-cylinder mixing performance of the CNG engine is proposed to explore the influencing rule of different engine speeds and loads on the mixing process and performance. The results indicate that phase space analysis can accurately reflect the characteristics of the mixture mixing process. The gas fuel mixture rapidly occupies the cylinder volume in the injection stage. During the transition stage, the gas fuel mixture is in a highly transient state. The diffusion stage is characterized by the continuous homogenization of the mixture. The in-cylinder mixing performance is linearly dependent on the engine’s working condition in the phase space. Full article
(This article belongs to the Special Issue Linear Motors and Direct-Drive Technology)
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30 pages, 30435 KiB  
Article
Design and Experimental Testing of an Ankle Rehabilitation Robot
by Ioan Doroftei, Cristina-Magda Cazacu and Stelian Alaci
Actuators 2023, 12(6), 238; https://doi.org/10.3390/act12060238 - 08 Jun 2023
Cited by 3 | Viewed by 1564
Abstract
The ankle joint (AJ) is a crucial joint in daily life, responsible for providing stability, mobility, and support to the lower limbs during routine activities such as walking, jumping, and running. Ankle joint injuries can occur due to sudden twists or turns, leading [...] Read more.
The ankle joint (AJ) is a crucial joint in daily life, responsible for providing stability, mobility, and support to the lower limbs during routine activities such as walking, jumping, and running. Ankle joint injuries can occur due to sudden twists or turns, leading to ligament sprains, strains, fractures, and dislocations that can cause pain, swelling, and limited mobility. When AJ trauma occurs, joint instability happens, causing mobility limitations or even a loss of joint mobility, and rehabilitation therapy is necessary. AJ rehabilitation is critical for those recovering from ankle injuries to regain strength, stability, and function. Common rehabilitation methods include rest, ice, compression, and elevation (RICE), physical therapy, ankle braces, and exercises to strengthen the surrounding muscles. Traditional rehabilitation therapies are limited and require constant presence from a therapist, but technological advancements offer new ways to fully recover from an injury. In recent decades there has been an upswing in research on robotics, specifically regarding rehabilitation. Robotic platforms (RbPs) offer several advantages for AJ rehabilitation assistance, including customized training programs, real-time feedback, improved performance monitoring, and increased patient engagement. These platforms use advanced technologies such as sensors, actuators, and virtual reality to help patients recover quicker and more efficiently. Furthermore, RbPs can provide a safe and controlled environment for patients who need to rebuild their strength and mobility. They can enable patients to focus on specific areas of weakness or instability and provide targeted training for faster recovery and reduced risk of re-injury. Unfortunately, high costs make it difficult to implement these systems in recuperative institutions, and the need for low-cost platforms is apparent. While different systems are currently being used, none of them fully satisfy patient needs or they lack technical problems. This paper addresses the conception, development, and implementation of rehabilitation platforms (RPs) that are adaptable to patients’ needs by presenting different design solutions (DSs) of ankle RPs, mathematical modeling, and simulations of a selected rehabilitation platform (RP) currently under development. In addition, some results from practical tests of the first prototype of this RP are presented. One patient voluntarily agreed to use this platform for more rehabilitation sessions on her AJ (right leg). To counteract some drawbacks of the first prototype, some improvements in the RP design have been proposed. The results on testing the improved prototype will be the subject of future work. Full article
(This article belongs to the Special Issue Advanced Robots: Design, Control and Application—2nd Edition)
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20 pages, 8255 KiB  
Article
Experimental Investigation on the Combined Blowing Control of a Hybrid Wing Body Aircraft
by Jiaxin Pan, Wanbo Wang, Chen Qin, Xunnian Wang, Qixiang Sun and Xin Zhang
Actuators 2023, 12(6), 237; https://doi.org/10.3390/act12060237 - 08 Jun 2023
Viewed by 1240
Abstract
Combined blowing was performed on a Hybrid Wing Body (HWB) aircraft through wind tunnel testing at a Reynolds number of 1.75 × 106. The full cycle of separation and reattachment under the control of combined blowing was implemented using Computational Fluid [...] Read more.
Combined blowing was performed on a Hybrid Wing Body (HWB) aircraft through wind tunnel testing at a Reynolds number of 1.75 × 106. The full cycle of separation and reattachment under the control of combined blowing was implemented using Computational Fluid Dynamics (CFD), and the mechanism of combined blowing inhibiting separation was analyzed. The aerodynamic characteristics of the baseline and the independent effects of the blown deflected trailing edge (TE), blown leading edge (LE), and combined blowing on the TE and LE were investigated. The results clearly show that combined blowing can inhibit the development of cross-flow, reduce the accumulation of a boundary layer at the tip, and inhibit the flow separation effect. The effect of using seamless simple flaps alone to increase the lift is limited; blowing control is required to enhance the lift further. Applying the blown deflected TE can improve the lift linear segment, so that 30° flap achieves the lift gain of 40° flap without control, while the drag coefficient is approximately 0.02 smaller, but the stall gradually advances. Using the blown LE can significantly increase the stall angle from 12° to 18°. However, the lift linear segment remains unaffected. In particular, combined blowing can achieve the control effect of improving the lift linear segment, delaying stall, and decreasing drag. Moreover, the maximum lift coefficient is approximately 0.19, and the lift-to-drag ratio increment in the control state with a 30° flap deflection angle is above 2.2 in the angle of attack range of 4° to 12° compared to the uncontrolled state with a 40° flap deflection angle. Full article
(This article belongs to the Special Issue Active Flow Control: Recent Advances in Fundamentals and Applications — Volume II)
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19 pages, 5304 KiB  
Article
Study on Life Prediction Method of Ball Screw Base on Constructed Degradation Feature and IGWO-BiLSTM
by Qin Wu, Jun Niu and Xinglian Wang
Actuators 2023, 12(6), 236; https://doi.org/10.3390/act12060236 - 07 Jun 2023
Viewed by 1261
Abstract
Regarding the problem of reduced remaining useful life (RUL) due to wear of the ball screw in the feed system of CNC (computer numerical control) machine tools, a prediction method based on constructing the degradation feature vector of the signal data and the [...] Read more.
Regarding the problem of reduced remaining useful life (RUL) due to wear of the ball screw in the feed system of CNC (computer numerical control) machine tools, a prediction method based on constructing the degradation feature vector of the signal data and the improved gray-wolf optimization with bidirectional long short-term memory (IGWO-BiLSTM) neural network regression model is proposed. Firstly, a time-domain analysis and the complete ensemble empirical mode decomposition with adaptive noise analysis (CEEMDAN) were carried out based on the collected life cycle signal data of a ball screw. The time-domain feature vector and the energy feature vector of each IMF (intrinsic mode function) component after CEEMDAN decomposition were constructed. The Pearson correlation coefficient was used to filter feature vectors and construct the multivariate feature vector. Secondly, this paper improves the traditional gray wolf optimization algorithm, adds a search strategy based on dimension learning, and combines the improved algorithm with the BiLSTM model, based on the IGWO-BiLSTM theory. A regression model between feature vectors and the remaining life of a ball-screw system was established. Finally, the prediction model was established according to the proposed method and compared with the other five neural network models: LSTM, BiLSTM, BO-LSTM (Bayesian optimization of LSTM), BO-BiLSTM, and IGWO-LSTM. The results indicate that this method has high accuracy and good generalization ability for predicting the remaining life of a ball-screw system. Full article
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21 pages, 3831 KiB  
Article
Model Order Reduction of Microactuators: Theory and Application
by Arwed Schütz and Tamara Bechtold
Actuators 2023, 12(6), 235; https://doi.org/10.3390/act12060235 - 07 Jun 2023
Cited by 1 | Viewed by 1150
Abstract
This paper provides an overview of techniques of compact modeling via model order reduction (MOR), emphasizing their application to cooperative microactuators. MOR creates highly efficient yet accurate surrogate models, facilitating design studies, optimization, closed-loop control and analyses of interacting components. This is particularly [...] Read more.
This paper provides an overview of techniques of compact modeling via model order reduction (MOR), emphasizing their application to cooperative microactuators. MOR creates highly efficient yet accurate surrogate models, facilitating design studies, optimization, closed-loop control and analyses of interacting components. This is particularly important for microactuators due to the variety of physical effects employed, their short time constants and the many nonlinear effects. Different approaches for linear, parametric and nonlinear dynamical systems are summarized. Three numerical case studies for selected methods complement the paper. The described case studies emerged from the Kick and Catch research project and within a framework of the German Research Foundation’s Priority Program, Cooperative Multistable Multistage Microactuator Systems (KOMMMA). Full article
(This article belongs to the Special Issue Cooperative Microactuator Devices and Systems)
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21 pages, 5272 KiB  
Article
Numerical Study on the Heating Effect of a Spring-Loaded Actuator—Part Ⅰ: Temperature and Humidity Distribution Characteristics
by Lei Xi, Zhen Zhao, Qicheng Ruan, Zhengheng Yang, Liang Xu, Jianmin Gao and Yunlong Li
Actuators 2023, 12(6), 234; https://doi.org/10.3390/act12060234 - 06 Jun 2023
Cited by 1 | Viewed by 1369
Abstract
Inappropriate distributions of temperature and humidity will cause the failure of the spring-loaded actuators. Therefore, it is essential to understand the temperature and humidity distribution characteristics in typical spring-loaded actuators, to guarantee the safe operation of the spring-loaded actuators. In this work, a [...] Read more.
Inappropriate distributions of temperature and humidity will cause the failure of the spring-loaded actuators. Therefore, it is essential to understand the temperature and humidity distribution characteristics in typical spring-loaded actuators, to guarantee the safe operation of the spring-loaded actuators. In this work, a numerical simulation study on the temperature and humidity distribution characteristics in a spring-loaded actuator was conducted. The influence laws of ambient temperature, heater power, and heater size on the temperature and humidity distributions inside the spring-loaded actuator were analyzed. The practical empirical correlations for the spring-loaded actuators were fitted. The results show that the air temperature around and directly above the heater is the highest and the corresponding relative humidity is the lowest. Then, the air temperature gradually decreases, and the relative humidity increases with the lateral flow of air. When the ambient temperature increases from 233.15 K (−40 °C) to 313.15 K (40 °C), the minimum temperature inside the actuator is increased by 34%, the maximum humidity first increases and then decreases, and the maximum temperature on the heater surface is increased by 30%. When the heating power increases from 10 W to 150 W at ambient temperatures of 273.15 K and 298.15 K, the minimum temperature inside the actuator is increased by 3.40% and 3.61%, the maximum humidity is decreased by 51.97% and 58.63%, and the maximum temperature on the heater surface is increased by 30.33% and 33.25%, respectively. The influence of heater length, width, and height on the minimum temperature and maximum relative humidity inside the spring-loaded actuator is relatively small. Within the study range, the increase in heater length, width, and height makes the maximum temperature on the heater surface decrease by 9.15%, 7.59%, 4.63% at ambient temperatures of 273.15 K, and 10.74%, 9.01%, 4.73% at ambient temperature of 298.15 K, respectively. The results may provide a reference for predicting temperature and humidity distributions inside general spring-loaded actuators and provide a calculation basis for the design of their heaters. Full article
(This article belongs to the Special Issue Actuators in 2022)
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21 pages, 15699 KiB  
Article
A New Performance Optimization Method for Linear Motor Feeding System
by Zeqing Yang, Wei Cui, Wenbo Zhang, Zhaohua Wang, Bingyin Zhang, Yingshu Chen, Ning Hu, Xiaoyang Bi and Wei Hu
Actuators 2023, 12(6), 233; https://doi.org/10.3390/act12060233 - 06 Jun 2023
Cited by 2 | Viewed by 1220
Abstract
The linear motor feeding system is a typical electromechanical coupling system. Conventional characteristic analyses of electromechanical coupling often overlook the influence of flexible deformation in critical components of the linear motor feeding system. Moreover, when employing genetic algorithms to optimize servo system PID [...] Read more.
The linear motor feeding system is a typical electromechanical coupling system. Conventional characteristic analyses of electromechanical coupling often overlook the influence of flexible deformation in critical components of the linear motor feeding system. Moreover, when employing genetic algorithms to optimize servo system PID control parameters, slow convergence, nonconvergence, or premature convergence problems may arise. To address these issues, this paper proposes a new performance optimization method for a linear motor feeding system. The method uses a combination of “multi-body theory + finite element” to accurately account for the flexible deformation of critical components of the feeding system, establishes a rigid–flexible electromechanical coupling model of the linear motor feeding system, and optimizes the PID parameters of the established model with an improved adaptive genetic algorithm. Simulation results demonstrate that, when utilizing an adaptive genetic algorithm to optimize the rigid–flexible electromechanical coupling model and a control system model that disregards flexible body deformation, the system achieves stability in 0.02 s and 0.027 s with overshoots of 13% and 27%, respectively. These outcomes confirm the accuracy and importance of considering flexible body deformation in the optimization performance of a linear motor feeding system. At the same time, the time required to reach the steady state of the rigid–flexible electromechanical coupling model optimized by the adaptive genetic algorithm is shortened from 0.035 s to 0.02 s. The sinusoidal signal response curve of the optimized system does not exhibit any peak overshoot compared with that of the nonoptimized system, and the response speed is also faster. These results demonstrate the effectiveness of the rigid–flexible electromechanical coupling model optimized by the nonlinear adaptive genetic algorithm. The displacement response curves of the linear motor feeding system under different workbench loads are obtained through experiments and compared with those obtained from simulations to verify the established model and the correctness of the proposed method. Full article
(This article belongs to the Section Control Systems)
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25 pages, 13315 KiB  
Article
High Precision Hybrid Torque Control for 4-DOF Redundant Parallel Robots under Variable Load
by Shengqiao Hu, Houcai Liu, Huimin Kang, Puren Ouyang, Zhicheng Liu and Zhengjie Cui
Actuators 2023, 12(6), 232; https://doi.org/10.3390/act12060232 - 05 Jun 2023
Cited by 2 | Viewed by 1135
Abstract
As regards the impact and chattering of 4-DOF redundant parallel robots that occur under high-speed variable load operating conditions, this study proposed a novel control algorithm based on torque feedforward and fuzzy computational torque feedback hybrid control, which considered both the joint friction [...] Read more.
As regards the impact and chattering of 4-DOF redundant parallel robots that occur under high-speed variable load operating conditions, this study proposed a novel control algorithm based on torque feedforward and fuzzy computational torque feedback hybrid control, which considered both the joint friction torque and the disturbance torque caused by the variable load. First of all, a modified dynamic model under variable load was established as follows: converting terminal load change to terminal centroid coordinate change, then mapping to the calculation of terminal energy, and lastly, establishing a dynamic model for each branch chain under variable load based on the Lagrange equation. Subsequently, torque feedforward was used to compensate for the friction torque and the disturbance torque caused by the variable load. Feedforward torques include friction torque and nonlinear disturbance torque under variable load. The friction torque is obtained by parameter identification based on the Stribeck friction model, while the nonlinear disturbance torque is obtained by real-time calculation based on the modified dynamic model under variable load. Finally, dynamic control of the robot under variable load was realized in combination with the fuzzy computational torque feedback control. The experimental and simulation results show that the motion accuracy of the fuzzy calculation torque feedback and torque feedforward control of the three drive joints of the robot under variable loads is 49.87%, 70.48%, and 50.37% lower than that of the fuzzy calculation torque feedback. Compared with pure torque feedback control, the speed stability of the three driving joints under fuzzy calculation torque feedback and torque feedforward control is 23.35%, 17.66%, and 25.04% higher, respectively. Full article
(This article belongs to the Special Issue Actuators in Robotic Control: Volume II)
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14 pages, 3093 KiB  
Article
Design and Simulation of a Single Piezoelectric-Driven Rotary Actuator with Double-Layer Flexible Mechanism
by Zhiyong Guo, Pengchao Zhao, Wenchao Zhang, Yanling Tian and Gaofeng Hu
Actuators 2023, 12(6), 231; https://doi.org/10.3390/act12060231 - 02 Jun 2023
Viewed by 1412
Abstract
A novel pure rotary actuator with a double-layer flexible mechanism (RA-DFM), which is driven by a single piezoelectric ceramic in the lower mechanism and generates rotational motion in the upper mechanism, is proposed in this paper. The output of piezoelectric ceramic is successively [...] Read more.
A novel pure rotary actuator with a double-layer flexible mechanism (RA-DFM), which is driven by a single piezoelectric ceramic in the lower mechanism and generates rotational motion in the upper mechanism, is proposed in this paper. The output of piezoelectric ceramic is successively amplified using an enhanced double Scott–Russell mechanism and two lever-type mechanisms to obtain a large rotation range. The static, kinematic and dynamic properties of the RA-DFM are numerically analyzed, and the actual output of the piezoelectric is analyzed considering the input stiffness. The geometric parameters of the RA-DFM are optimized based on the constructed numerical models. Finite element analysis has been implemented to validate the correctness of the theoretical models and further evaluate the output property. The simulation results show the maximal rotation angle of the RA-DFM is 15.14 mrad with 0.44% center drift. Full article
(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)
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17 pages, 762 KiB  
Article
Currents Analysis of a Brushless Motor with Inverter Faults—Part II: Diagnostic Method for Open-Circuit Fault Isolation
by Cristina Morel, Baptiste Le Gueux, Sébastien Rivero and Saad Chahba
Actuators 2023, 12(6), 230; https://doi.org/10.3390/act12060230 - 02 Jun 2023
Cited by 1 | Viewed by 876
Abstract
In this paper, a brushless motor with a three-phase inverter is investigated under healthy and multiple open-circuit faults. The occurrence of faults in an inverter will lead to atypical characteristics in the current measurements. This is why many usual entropies and multiscale entropies [...] Read more.
In this paper, a brushless motor with a three-phase inverter is investigated under healthy and multiple open-circuit faults. The occurrence of faults in an inverter will lead to atypical characteristics in the current measurements. This is why many usual entropies and multiscale entropies have been proposed to evaluate the complexity of the output currents by quantifying such dynamic changes. Among this multitude of entropies, only some are able to differentiate between healthy and faulty open-circuit conditions. In addition, another selection is made between these entropies in order to improve diagnostic speed. After the fault detection based on the mean values, the open-circuit faults are localized based on the fault diagnostic method. The simulation results ensure the ability of these entropies to detect and locate open-circuit faults. Moreover, they are able to achieve fault diagnostics for a single switch, double switches, three switches, and even four switches. The diagnostic time to detect and to isolate faults is between 10.85 ms and 13.67 ms. Then, in order to prove the ability of the fault diagnostic method, a load variation is performed under the rated speed conditions of the brushless motor. The validity of the method is analyzed under different speed values for a constant torque. Finally, the fault diagnostic method is independent from power levels. Full article
(This article belongs to the Special Issue Linear Motors and Direct-Drive Technology)
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19 pages, 13524 KiB  
Article
Flow Separation Control of Nacelle Inlets in Crosswinds by Dielectric Barrier Discharge Plasma Actuation
by Dongsheng Zhang, Hua Liang, Hesen Yang, Zhi Su, Chuanbiao Zhang and Shimin Liu
Actuators 2023, 12(6), 229; https://doi.org/10.3390/act12060229 - 31 May 2023
Viewed by 1010
Abstract
Crosswinds will lead to large-scale flow separation in the nacelle inlets, which seriously affects the flight safety of the aircraft; there is an urgent need to develop flow control measures. As a plasma flow control method, the application of surface dielectric barrier discharge [...] Read more.
Crosswinds will lead to large-scale flow separation in the nacelle inlets, which seriously affects the flight safety of the aircraft; there is an urgent need to develop flow control measures. As a plasma flow control method, the application of surface dielectric barrier discharge in the field of nacelle inlet separation control is of great significance for improving the intake quality. Based on the characteristic law of the baseline flow field, the flow control effect of the nacelle inlet separation flow field experiments with NS-DBD, and the influence of the actuation frequency on the flow control is discussed. A comparative experimental study of NS-DBD and AC-DBD is carried out. Finally, the flow control mechanisms for both are discussed. The results show that under the condition that the flow velocity of the wind tunnel is 35 m/s and the crosswind angle is 10°, the average total pressure loss coefficient and distortion index decrease by 29.62% and 44.14% by NS-DBD actuation. At the same time, exists an inherent optimal coupling frequency in NS-DBD, and the control effect of NS-DBD is better than that of AC-DBD. NS-DBD mainly through shock waves and induced vortices, while AC-DBD mainly through the induced generation of near-wall jets to reduce the inverse pressure gradient and improve nacelle flow separation. Full article
(This article belongs to the Section Aircraft Actuators)
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